Visual editor adds span tags with style by itself

I have noticed that the wordpress visual editor adds span tags with no reason. It happens when I create a bullet list or when I make a link.

I am able to reproduce the bug for bullet lists but I cant do it for the links. It seems to happen randomly.

To reproduce the bug for bullet list, I start with a title H3 then I click on the bullet list button. I start to write the list and then, when i save the draft, the first line has a span tag. This bug happens in several websites. Sometimes i get something like this :

<li><span style="line-height: 12.997159004211426px;"><strong>
or

<span style="font-size: 13px; line-height: 19px;">

I dont paste text from word to the visual editor. I write directy in the visual editor.

For links, I dont know when it happens, but I sometimes have a <span style="color:#333333">.

First, I thought i had the same bug than this one : #23461 which said it was a "long standing bug in WebKit"
but i had this bug in Firefox too which is not using Webkit but Gecko.

Then i thought it was a bug with the add_editor_style() function but it's not that too. I commented the function but the bug still happens.

Spent a lot of time testing this, triggered by line-height in the editor stylesheets. Until this is fixed in Chrome, seems the only workaround is to not define line-height for any element, especially not on the <body> and <br>.